Plugin settings. How to add Rich Text Area?

Description of issue or problem I’m having:
I am trying to add a rich text field to the settings form for a plugin that I am developing, but I don’t seem to be able to get the TinyMCE editor to work in the form.

Steps I took leading up to the issue:
I have followed the plugin developers guide but there are no specific examples that show how to add a rich text OR html field to the settings form.
I have tried field type: text, textarea, richtextarea, field-html and a few other random options. Text and textarea work but I do need to be able to paste in HTML code to be displayed on the frontend.

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What I tried to resolve the issue:
Reading through the documentation I was hoping to find some examples of all the available fields that can be used in the settings form but I can’t find any examples of using something more advanced than a simple textarea field.

Application Version - e.g., OJS 3.1.2:

Is there a documented list of field types that I can use in the plugin settings form? If not that, then perhaps someone here has already done this before and could tell me what the secret is? :slight_smile:

Many thanks,